JPH05258933A - Magnetic characteristic improving method of resin magnet molded product - Google Patents

Abstract

PURPOSE:To devise the title method of efficiently increasing the surface magnetic flux density of a molded product containing polyarylenesulfide resin and magnetic powder. CONSTITUTION:A magnetized and molded product containing polyarylelesulfide resin and magnetic powder is aged in a magnetic field at the temperature exceeding 50 deg.C but not exceeding the meltdown starting temperature of polyarylenesulfide until the surface magnetic flux density of the molded product is increased by more than 2%.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for improving the magnetic properties of resin magnet moldings.

[0002]

2. Description of the Related Art A molded article containing a polyarylene sulfide resin and magnetic powder makes use of the excellent properties such as heat resistance, chemical resistance and low water absorption of the polyarylene sulfide resin, in the fields of automobile materials, electronic materials, It is becoming more and more important in the fields of home electric appliances and industrial materials.
On the other hand, in each of the above fields in which the molded product is used, superior magnetic properties have been demanded for the molded product. In particular, among the magnetic properties of the molded article, increasing the surface magnetic flux density is particularly important for the use of the article. For example, in a tachometer sensor, the higher the surface magnetic flux density, the higher the degree of freedom in design or the detection sensitivity.

Conventionally, in order to improve the surface magnetic flux density of a molded product containing a polyarylene sulfide resin and magnetic powder, a method of increasing the content of the magnetic powder in the molded product has been adopted. However, this method has a problem that the fluidity of the resin composition is remarkably reduced and molding becomes difficult.

[0004]

An object of the present invention is to provide a method for efficiently improving the surface magnetic flux density of a molded article containing a polyarylene sulfide resin and magnetic powder.

[0005]

The present invention provides a method for achieving the above-mentioned object, that is, a magnetized molded article containing a polyarylene sulfide resin powder and a magnetic powder at 50 ° C. or higher,
The present invention provides a method for improving the magnetic properties of a resin magnet molded article, which comprises aging at a temperature lower than the melting start temperature of polyarylene sulfide until the surface magnetic flux density of the molded article is increased by 2% or more. ..

[0006]

DETAILED DESCRIPTION OF THE INVENTION In the present invention, any magnetized molded article containing a polyarylene sulfide resin and magnetic powder can be used, but preferably the surface magnetic flux density is 0.3 gauss or more, Preferably, a molded product of 1 gauss or more is used for efficiently improving the surface magnetic flux density by aging.

A magnetized molded article containing a polyarylene sulfide resin and magnetic powder used in the present invention is
5% by weight or more and 30% by weight or less, more preferably 5% by weight or more and 20% by weight or less of polyarylene sulfide resin, and 70% by weight or more and 95% by weight or less of magnetic powder,
More preferably, the content is 80% by weight or more and 95% by weight or less, and the components other than the polyarylene sulfide resin and the magnetic powder are 0% by weight or more and 25% by weight or less.

Here, the polyarylene sulfide resin means 50% by weight of-(-Ar-S-)-(where "-Ar-" means an arylene group) as a main constituent unit.
Or more, preferably 70% by weight or more, more preferably 90% by weight
It is a polymer containing at least wt% and having a crystal melting point recognized by a differential scanning calorimeter (DSC). Among them, polyarylene sulfide having a substantially linear structure obtained from a monomer mainly composed of a bifunctional monomer is preferable because it has excellent toughness. However, even if it partially contains a crosslinked structure or is subjected to a treatment for increasing the melt viscosity (curing) by oxidative crosslinking, it can be used as long as the mechanical properties are not impaired.

Particularly preferred as-(-Ar-S-)-is a p-phenylene sulfide unit represented by the following chemical formula 1.

[0010]

[Chemical 1] Is.

Further, the polyarylene sulfide resin is
It may be a homopolymer, a random copolymer, or a block copolymer. In the case of a copolymer, the p-phenylene sulfide shown in Chemical formula 1
0 wt% or more, especially 60 wt% or more,

[0012]

[Chemical 2]

M-phenylene sulfide unit, diphenylene sulfide unit, trifunctional phenylene sulfide unit, 2,6-naphthalene sulfide unit, phenyl ketone phenyl sulfide unit, phenyl sulfone unit, phenyl ether phenyl sulfide unit, phenyl sulfone phenyl Either sulfide unit or phenylketone phenylketone phenylsulfide unit 1
It is preferably used that the content of the seeds is 50% by weight or less, and particularly 40% by weight or less.

The melt viscosity of the polyarylene sulfide resin is not particularly limited as long as it can be stably melt-kneaded and can be melt-molded from a mixture with magnetic powder such as melt extrusion molding and injection molding.

The magnetic powder used in the present invention is not particularly limited, but magnetoplumbite type ferrite such as Ba ferrite and Sr ferrite, samarium-cobalt alloy type magnetic powder or neodymium-iron-boron type magnetic powder. Rare earth magnetic powder such as powder, Alnico 5, Alnico 8, iron-chromium-cobalt type metal alloy, Mg-Mn type ferrite, Ni-Al type ferrite, spinel type ferrite such as Li type ferrite, γ-ferrite, cobalt-γ -Ferrite and the like are preferred.

Above all, a hard magnetic material such as a magnetoplumbite type ferrite such as Ba ferrite or Sr ferrite, or a rare earth magnetic powder such as samarium-cobalt alloy magnetic powder or neodymium-iron-boron magnetic powder effectively exerts magnetic characteristics. It is particularly preferable for improvement.

The magnetic powder used in the present invention may be surface-treated with a known surface treatment agent such as a silane coupling agent, a titanate coupling agent or an aluminum coupling agent.
Further, the surface of the magnetic powder used in the present invention may be stabilized with a dye, a passivating agent or the like without any problem.

In the present invention, the components other than the polyarylene sulfide resin and the magnetic powder are contained in an amount of 0% by weight to 25% by weight.
It is possible to contain the following, but as the component, glass fibers, carbon fibers, potassium titanate, asbestos, silicon carbide, ceramic fibers, metal fibers, fibrous inorganic reinforcing agents such as silicon nitride, fibers such as aramid fibers Organic strengthening agent,
Thermoplastic resins such as polyamide, polyphenylene ether, polyether ether ketone, polyether ketone, polycarbonate and polystyrene, and thermosetting resins such as epoxy resin are preferable. The mixed form is not limited to the composition, and may be a non-uniform form such as a cloth form.

In the process of melting and mixing the above components and molding them into a predetermined shape in a mold, the mixture is melted in the mold, or after the molding and solidification, a magnetic field is applied to magnetize the molding. Get the goods. Various methods are known for this purpose.

In the present invention, the magnetized molded article obtained as described above is heated to 50 ° C. or higher and lower than the melting start temperature of the polyarylene sulfide resin to have a surface magnetic flux density of 2% or higher. More preferably, the aging is performed until it is increased by 3% or more, and even more preferably by 5% or more. At a temperature of less than 50 ° C., it is difficult to efficiently improve the surface magnetic flux density even if the molded product is aged. On the other hand, at a temperature above the melting start temperature, the surface magnetic flux density of the molded product becomes rather small.

The term "aging" as used in the present invention means a treatment for stabilizing and improving the magnetic properties of a molded article containing a magnetic powder for a specific time under an environment of a specific temperature. Say.

Here, the melting start temperature is the rising temperature of the endothermic peak accompanying the melting of the polyarylene sulfide when the temperature is raised at 10 ° C./min in DSC.

The temperature for aging is preferably 9
The temperature is 0 ° C or higher and 30 ° C or lower below the melting start temperature, more preferably 100 ° C or higher and 50 ° C below the melting start temperature.
A temperature range up to and including ℃ lower temperature is used.

Further, the time for aging the molded product depends on the shape and weight of the molded product and is not generally determined, but a time of 5 minutes or more and 72 hours or less is preferable. A time of 5 minutes or less is usually not sufficient to improve the surface magnetic flux density of the molded product by at least 2% or more, and aging for a time of more than 72 hours is another object of the present invention. It is not preferable from the viewpoint of efficiently improving the surface magnetic flux density of the molded product.

Further, in the present invention, an external magnetic field may be applied during aging, but in this case, the strength of the external magnetic field is preferably 0.5 Oersted or more and 100,000 Oersted or less. A magnetic field of less than 0.5 oersted is not efficient in improving the surface magnetic flux density of the molded product, while efficiently applying a magnetic field of more than 100,000 oersted to the surface magnetic flux density of the molded product. Because it is difficult.

[0026]

EXAMPLES Next, the present invention will be described in more detail with reference to Examples.

[Examples 1 to 4] A composition of 18% by weight of polyphenylene sulfide resin (melting start temperature: 250 ° C) and 82% by weight of Sr ferrite was used as PS / E type manufactured by Nissei Plastic Industry Co., Ltd. equipped with a magnetic field applying device. Supply to injection molding machine,
Diameter 2 while applying a magnetic field (about 5000 Oersted)
A disk with a diameter of 0 mm and a thickness of 7 mm and a diameter of 6.5 m at its center
It was molded into a shape in which a m rod was inserted. The surface magnetic flux density of the obtained molded product before aging was measured with a Gauss meter manufactured by Yokogawa Electric.

These molded products were subjected to temperature and time aging shown in Table 1 below. After aging, the molded product was cooled to room temperature in a desiccator, and the surface magnetic flux density of the molded product was measured. The measurement results are shown in Table 1 together with the results of Comparative Examples described below.

[0029]

[Table 1]

[Comparative Example 1] Molded articles similar to those in Examples 1 to 4 were placed at room temperature (23 ° C) for 2 weeks for aging.
The surface magnetic flux density of the molded product before aging was 1010 gauss. The surface magnetic flux density of the molded product after aging was 1010 gauss.

[Comparative Example 2] Molded articles similar to those of Examples 1 to 4 were placed at 270 ° C for 15 minutes and aged. The surface magnetic flux density of the molded product before aging was 1015 gauss. On the other hand, when the surface magnetic flux density of the molded product was measured after aging, it was 850 Gauss.

[Comparative Example 3] Molded articles similar to those in Examples 1 to 4 were molded. The surface magnetic flux density of the obtained molded product before aging was 1015 gauss. Further, the molded product was demagnetized to have a surface magnetic flux density of 0.1 Gauss or less.
Next, it was placed at 150 ° C. for 1 hour for aging. After aging, the molded product was placed in a mold and magnetized again. When the surface magnetic flux density of the re-magnetized molded product was measured, it was 102
It was 0 gauss.

The results of Comparative Examples 1 to 4 are shown in Table 1 above together with the results of Examples 1 to 4.

[Examples 5 to 8] A composition containing 15% by weight of polyphenylene sulfide resin and 85% by weight of Ba ferrite was supplied to a PS / E type injection molding machine manufactured by NISSEI PLASTIC INDUSTRIAL CO., LTD., Diameter 20 mm, thickness 7 mm. A molded product having the shape shown on the disk was molded. Then, the obtained molded product was subjected to a maximum of 1000 at room temperature with a DC magnetometer manufactured by Electronic Magnetic Industry Co., Ltd.
Magnetization was performed by applying an external magnetic field of 0 Oersted. The surface magnetic flux density of the obtained molded product before aging was measured with a Gauss meter manufactured by Yokogawa Electric. After that, these molded products were aged at the temperature and time shown in Table 2. After aging, the molded product was cooled to room temperature in a desiccator, and the surface magnetic flux density of the molded product was measured.

[0035]

[Table 2]

[Comparative Example 4] Molded articles similar to those in Examples 5 to 8 were placed at room temperature (23 ° C) for 2 weeks and aged.
The surface magnetic flux density of the molded product before aging was 1300 gauss. Further, the surface magnetic flux density of the molded product after aging was measured and found to be 1030 gauss, and no difference was observed.

[Comparative Example 5] Molded articles similar to those in Examples 5 to 8 were placed at 270 ° C for 15 minutes for aging. The surface magnetic flux density of the molded product before aging was 1295 gauss. On the other hand, when the surface magnetic flux density of the molded product after aging was measured, it was 1080 Gauss, which was rather low.

The results of Comparative Examples 4 to 5 are also shown in Table 2 above.
Shown in.

[0039]

As described above, according to the present invention, it is possible to efficiently improve the surface magnetic flux density of a molded product without increasing the filling amount of the magnetic powder which causes the deterioration of fluidity in the molding process. is there.

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[Procedure amendment]

[Submission date] November 6, 1992

[Procedure Amendment 1]

[Document name to be amended] Statement

[Name of item to be amended] Claims

[Correction method] Change

[Correction content]

[Claims]

[Procedure Amendment 2]

[Document name to be amended] Statement

[Correction target item name] 0005

[Correction method] Change

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[0005]

The present invention provides a method for achieving the above-mentioned object, that is, a magnetized molded article containing a polyarylene sulfide resin powder and a magnetic powder in a magnetic field.
Provided is a method for improving magnetic properties of a resin magnet molded article, which comprises performing aging at a temperature of 0 ° C. or higher and lower than a melting start temperature of polyarylene sulfide until the surface magnetic flux density of the molded article is increased by 2% or more. To do.

[Procedure 3]

[Document name to be amended] Statement

[Correction target item name] 0013

[Correction method] Change

[Correction content]

An m-phenylene sulfide unit represented by:
Diphenylene sulfide unit, trifunctional phenylene sulfide unit, naphthylene sulfide unit, phenyl ketone phenyl sulfide unit, phenyl sulfone unit,
A phenyl ether phenyl sulfide unit, a phenyl sulfone phenyl sulfide unit, or a phenyl ketone phenyl ketone phenyl sulfide unit is preferably used in an amount of 50 wt% or less, particularly 40 wt% or less.

[Procedure amendment 4]

[Document name to be amended] Statement

[Correction target item name] 0020

[Correction method] Change

[Correction content]

In the present invention, the magnetized molded article obtained as described above is heated in a magnetic field at a temperature of 50 ° C. or higher and lower than the melting start temperature of the polyarylene sulfide resin to obtain a surface magnetic flux density of 2 % Or more, more preferably 3% or more, and even more preferably 5% or more. At a temperature of less than 50 ° C., it is difficult to efficiently improve the surface magnetic flux density even if the molded product is aged. On the other hand, at a temperature above the melting start temperature, the surface magnetic flux density of the molded product becomes rather small.

[Procedure Amendment 5]

[Document name to be amended] Statement

[Correction target item name] 0021

[Correction method] Change

[Correction content]

Although aging is performed in a magnetic field in the present invention, the magnetic field may be an internal magnetic field or an external magnetic field. The strength of the external magnetic field is preferably 0.5 Oersted or more and 100,000 Oersted or less.
A magnetic field of less than 0.5 oersted is not efficient in improving the surface magnetic flux density of the molded product, while efficiently applying a magnetic field of more than 100,000 oersted to the surface magnetic flux density of the molded product. Because it is difficult.

[Procedure correction 6]

[Document name to be amended] Statement

[Name of item to be corrected] 0022

[Correction method] Delete

[Procedure Amendment 7]

[Document name to be amended] Statement

[Name of item to be corrected] 0025

[Correction method] Change

[Correction content]

The aging referred to in the present invention is a treatment for stabilizing a magnetic property of the molded product by improving the magnetic properties of the molded product by placing the molded product containing the magnetic powder for a specific time in an environment of a specific temperature. Say. Here, the melting start temperature is
It is the rising temperature of the endothermic peak accompanying the melting of polyarylene sulfide when the temperature is raised at 10 ° C./min in DSC.

[Procedure Amendment 8]

[Document name to be amended] Statement

[Correction target item name] 0033

[Correction method] Change

[Correction content]

The results of Comparative Examples 1 to 3 are shown in Table 1 above together with the results of Examples 1 to 4.

Claims (1)

[Claims] 1. A magnetized molded article containing a polyarylene sulfide resin and magnetic powder is increased in surface magnetic flux density by 2% or more at a temperature of 50 ° C. or higher and below the melting start temperature of the polyarylene sulfide resin. A method for improving magnetic properties of resin magnet molded products, characterized by performing aging up to.